A Study Of The Practical Application Of On-line Monitoring In Substation Arresters And Its Influencing Factors

The safe operation of the power grid has become the primary goal of the power enterprise.As an important equipment to resist the internal and external over-voltages of the power system,the operation of the equipment is particularly important.With the development of power grid construction,the number of surge arresters installed in power substations has increased rapidly.The effectiveness of arrester detection has also become the focus of power enterprises.Means of arrester detection have updated from power outage test,live detection,on-line monitoring test,both at home and abroad,among which the on-line monitoring has realized the real-time monitoring of the data volume.But the high device failure rate,the high rate of false system alarm and the additional maintenance work have become the new concerns for enterprises.Fujian Electric Power Co.,Ltd.has been taking the lead in on-line monitoring technology among those state grid corporations.Putian Power Company,as a subordinate unit,has put SPM-type hierarchical distributed power line monitoring system into operation in 12 220kV substations by the end of 2015.By means of data collection,basic diagnosis,fault alarm and other modules,real-time data monitoring of the whole current,capacitive current,resistive current,lightning strike time and lightning strike of the arrester is realized,which meets the requirements of arrester operation.Although the parameters of the on-line monitoring are complete,the data obtained by the current monitoring technology can not completely eliminate the influence of interference factors.Data anomalies and fluctuations often occur,which affect the diagnosis of the arrester equipment real condition.In order to improve the effectiveness of online monitoring applications so as to replace power outage testing and live detection,and achieve the progressive realization of practical online detection,the company continue to carry out on-line monitoring,including arrester practical analysis.Local cities and towns also arrange some substations to carry out on-line monitoring data comparison.Among them,Putian Power Supply Company has installed 435 sets of arrester on-line monitoring devices in substations within its jurisdiction,which can offer a large number of on-site measured data for practical analysis.Based on the actual work background,this paper analyzes the principle,detection means and on-line monitoring system of substation lightning arrester.What's more,this paper analyzes the defects detection rate,false alarm rate,and then analyzes the data of arrester on-line monitoring based on mathematical morphology filtering and fitting algorithm.The results show that the full-current data can meet the requirements of practical application,but resistive current data with a deviation of more than 30%still need to rule out confounding factors so at to improve effectiveness.And then combined with successful cases of the practical application of online monitoring,from the monitoring data to the disintegration of the causes of defects,the effectiveness of online monitoring applications can be confirmed.Afterwards,combined with cases of false alarms of online monitoring and the factors influencing the accuracy of the test data,such as the selection of base,temperature and humidity,communication failure,resistive current test method and meter quality,some suggestions are proposed to eliminate the interphase interference.Finally,according to the characteristics of different on-line monitoring data corresponding to different fault types,an on-line identification analysis method of arrester defect is put forward to improve the effectiveness of on-line monitoring data of arrester equipment,so as to promote on-line monitoring technology in substations,and to ensure safe and stable operation of power grid equipment.Therefore,this research is of great guiding significance and application value.